new helper: file_inode(file)

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/fs/compat_ioctl.c b/fs/compat_ioctl.c
index e2f57a0..3ced75f 100644
--- a/fs/compat_ioctl.c
+++ b/fs/compat_ioctl.c
@@ -1582,7 +1582,7 @@
 	case FIBMAP:
 	case FIGETBSZ:
 	case FIONREAD:
-		if (S_ISREG(f.file->f_path.dentry->d_inode->i_mode))
+		if (S_ISREG(file_inode(f.file)->i_mode))
 			break;
 		/*FALL THROUGH*/